From: elasota <1137273+elasota@users.noreply.github.com>
Date: Thu, 9 Nov 2023 04:46:37 +0000 (-0500)
Subject: Clarify that there must be at least 2 weights, i.e. encoding all weights as 0 is... 
X-Git-Tag: v1.5.6^2~95
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=05059e5a48333e594e0204894cbbdffe51305487;p=thirdparty%2Fzstd.git

Clarify that there must be at least 2 weights, i.e. encoding all weights as 0 is invalid
---

diff --git a/doc/zstd_compression_format.md b/doc/zstd_compression_format.md
index dbf409eac..4a8d338b7 100644
--- a/doc/zstd_compression_format.md
+++ b/doc/zstd_compression_format.md
@@ -1252,7 +1252,9 @@ Number_of_Bits = Weight ? (Max_Number_of_Bits + 1 - Weight) : 0
 ```
 When a literal value is not present, it receives a `Weight` of 0.
 The least frequent symbol receives a `Weight` of 1.
-If no symbol has a `Weight` of 1, then the data is considered corrupted.
+If no literal has a `Weight` of 1, then the data is considered corrupted.
+If there are not at least two literals with non-zero `Weight`, then the data
+is considered corrupted.
 The most frequent symbol receives a `Weight` anywhere between 1 and 11 (max).
 The last symbol's `Weight` is deduced from previously retrieved Weights,
 by completing to the nearest power of 2. It's necessarily non 0.